Hybrid lead halide perovskite solar cells (PSCs) have emerged as potential competitors to silicon-based solar cells with an unprecedented increase in power conversion efficiency (PCE), nearing the breakthrough point toward commercialization. However,f or hole-transporting materials, it is generally acknowledged that complex structures often create issues such as increased costs and hazardous substances in the synthetic schemes,when translated from the laboratory to manufacture on al arge scale.H ere,w ep resent cyclobutanebased hole-selective materials synthesized using simple and green-chemistry inspired protocols in order to reduce costs and adverse environmental impact. As eries of novel semiconductors with molecularly engineered side arms were successfully applied in perovskite solar cells. V1366-based PSCs feature impressive efficiency of 21 %, along with long-term operational stability under atmospheric environment. Most importantly,w ea lso fabricated perovskite solar modules exhibiting arecordefficiency over 19 %with an active area of 30.24 cm 2 .

A cost-effective dopant-free fluorene-based enamine as a hole transport material for semi-transparent Sb2S3 solar cells is successfully demonstrated.

Novel cross-linkable carbazole-based HTMs for inverted perovskite solar cells are designed with 16.9% power conversion efficiency and good stability.

In this study, a series of donor-acceptor-donor (D-A-D) type small molecules based on the fluorene and diphenylethenyl enamine units, which are distinguished by different acceptors, as holetransporting materials (HTMs) for perovskite solar cells is presented. The incorporation of the malononitrile acceptor units is found to be beneficial for not only carrier transportation but also defects passivation via Pb-N interactions. The highest power conversion efficiency of over 22% is achieved on cells based on V1359, which is higher than that of spiro-OMeTAD under identical conditions. This st shows that HTMs prepared via simplified synthetic routes are not only a low-cost alternative to spiro-OMeTAD but also outperform in efficiency and stability state-of-art materials obtained via expensive cross-coupling methods.

Hybrid lead halide perovskite solar cells (PSCs) have emerged as potential competitors to silicon-based solar cells with an unprecedented increase in power conversion efficiency (PCE), nearing the breakthrough point toward commercialization. However,f or hole-transporting materials, it is generally acknowledged that complex structures often create issues such as increased costs and hazardous substances in the synthetic schemes,when translated from the laboratory to manufacture on al arge scale.H ere,w ep resent cyclobutanebased hole-selective materials synthesized using simple and green-chemistry inspired protocols in order to reduce costs and adverse environmental impact. As eries of novel semiconductors with molecularly engineered side arms were successfully applied in perovskite solar cells. V1366-based PSCs feature impressive efficiency of 21 %, along with long-term operational stability under atmospheric environment. Most importantly,w ea lso fabricated perovskite solar modules exhibiting arecordefficiency over 19 %with an active area of 30.24 cm 2 .